I have for a long time now used a diamant sharpener for my exel #11 blades.
I guess we all have problem with the blades loosening it's sharpness in a short time.
With this sharpener I have the same blade for weeks!
Cost almost nothing in the sport utility shops, and easy to use.
[Blocked Image: http://home.online.no/~roald-sv/div/sharpener.jpg]